In the field of home, office, and/or consumer-oriented robotics, mobile robots performing household functions involving traversing a floor or other surface to vacuum cleaning, floor wash, patrol, or cut a lawn, have become commercially available. Machines for clearing debris from carpet or hard floors, for example, may traverse a carpet or hard floor surface, for example. In the course of moving over the floor or other such surface, these robots may odometrically monitor the distance they travel, or determine whether they are in fact moving, by counting the number of, or monitoring, revolutions made by a rotatable wheel that remains in frictional contact with the surface while the robot moves over the surface.